This invention relates to a novel method of constructing electrical devices and the electrical devices constructed thereby and more particularly the invention relates to a method of constructing electrical devices wherein the circuit and other components thereof are connected together by circuit paths stamped from a sheet of metal and encapsulated in plastic, with the stamped conductive paths and the plastic together forming terminals and housing receptacles for the various components employed in the electrical device.
The development of the structural characteristics of electrical devices and the method of making them has progressed from the stage wherein relatively large individual components were mounted on metal chassies and interconnected by discrete wire conductors soldered to terminals to modern day techniques wherein large scale integrated (LSI) circuit chips, each containing thousands of semiconductor devices, are formed on a tiny substrate, measuring perhaps a half an inch on a side. Intermediate stages in the development of electronic manufacturing techniques has included printed circuit boards with discrete components, such as transistors, resistors, capacitors and inductors mounted thereon. More recently, with the development of the LSI chip, techniques have been developed for mounting such LSI chip upon printed circuit boards or other substrates by means of spider assemblies and/or lead frame structures which are now well known in the art. Components external to the LSI chip, which can include discrete components such as oscillators, capacitors, inductors, resistors or display devices, for example, are frequently mounted directly upon the printed circuit board by solder or retained in sockets or connectors which in turn are mounted upon the circuit board. The interconnections between the various circuit components and the terminals on the edge of the LSI chip are conductive paths formed by well known means upon the surface of the printed circuit board. In some instances the circuit board is multi-layered with two or more layers of conductive circuit paths interconnected by plated-through holes at selected points in the assembly. One currently prevelant form of mounting an LSI chip upon a printed circuit board is a packaging technique known as a dual-in-line package (DIP) which consists primarily of a plastic housing containing the LSI chip and having two rows of terminals connected at one end to the LSI terminals, usually by means of a spider assembly, and having the other ends extending from the sides of the plastic housing and inserted directly into apertures formed in a printed circuit board or into a socket which in turn is mounted upon a printed circuit board.
By its very nature a printed circuit board involves the soldering of discrete components thereon and, in many cases, the use of special connectors or sockets by which components are secured thereon. Such sockets or connectors can be in the form of female receptacles individually inserted in holes in the printed circuit board and which receive the terminals of a component, or can be sockets which are soldered directly to the surface of the circuit board or have terminals which fit within apertures in the circuit board with circuit component mounted upon female terminals formed in the socket.
The cost of an assembly including a printed circuit board with the various connectors needed to connect and retain components thereupon can be quite high, not only in the fabrication of the printed circuit board but also in the fabrication of the connectors and the mounting of the components either directly upon the board or upon the connectors.